In late May, hacker artist David Huerta, co-organizer of Art Hack Day and Cryptoparty, sent the NSA one hell of a snail mail. Huerta built a DIY encrypted mixtape using an Arduino board and a transparent acrylic case, containing a "soundtrack for the modern surveillance state." It's a mixtape the NSA won't be able to listen to because of the power of private key-based cryptography.

"I made my own version of a mixtape with an Arduino and wave shield sandwiched in between two laser-etched pieces of transparent acrylic," he wrote. "The use of a giant-ass Arduino and wave shield was chosen since the (shitty) 44KHz wave file format gave it roughly the same audio quality I figured a wiretapped AT&T phone conversation would have."

Huerta settled on the transparent acrylic cassette casing as a symbolic gesture of transparency.